For the winding of elongate members or cores for use in wire wound resistors, coils and transformers in electrical or electronic equipment, winding machines are known which with respect to their function can be divided in a number of principal types, such as disclosed in the specification of applicants' international patent application PCT/DK79/00008, international publication No. WO79/00763.
For the winding of closed members, winding machines of the so-called single-ring type are normally used in case of smaller wire dimensions, and winding machines of the so-called double-ring type in case of greater wire dimensions. Machines of the single-ring type are superior with respect to the winding speed, whereas the requirements to accurate positioning of the winding wire on the core which arises, for example, in case of controllable resistors or transformers are fulfilled to a greater extent by winding machines of the double-ring type.
From U.S. Pat. No. 2,974,890 a winding machine of the single-ring type is known operating in accordance with an immediate or direct winding procedure, which means that winding wire is supplied to a wire magazine in the machine in the same operation in which wire is drawn out from the rotating wire magazine for winding of the core. In this prior art machine, the wire magazine comprises two rings of circular cross-section which are kept in mutual engagement with a common axis of revolution by three pulley-shaped rollers, one of which is pressed against the magazine with an adjustable contact pressure so as to maintain the wire tension during the drawing of the wire between the rings within desirable limits. However, this prior art machine has not found any application in practice, mainly due to the following disadvantages.
In order to enable a selective wire-drawing, the wire diameter must be great relative to the cross-sectional diameter of the two magazine rings, whereby, in addition to a limited applicability with respect to wire dimensions, inferior residual hole conditions in the winding of endless members will result.
The winding object must be centrally positioned with respect to the wire magazine, since an excentrical location will result in an acute drawing angle, whereby the wire tension will be mainly tangential relative to the magazine with the resulting risk of slipping of the wire in the drawing slit between the two rings. Also this requirement results in inferior residual hole conditions in the winding of endless members.
Moreover, since the prior art winding machine described does not comprise any holding means for the wire supply left in the wire magazine between the two rings after cutting of the winding wire, so that the supply of wire into the magazine must be continued right to the end of the winding operation, a return coiling of the wire surplus in the magazine must be performed after each wire operation, if a great overconsumption of winding wire should be avoided.
In addition, it is common to the prior art winding machines that they can only be used together with a specific type of wire magazine, since accurate matching is required between the wire magazine and the magazine holder of the winding machine with guide means for the wire magazine, so that it is not possible with one and the same winding machine to comply with the different requirements as to the design of the wire magazine which are made in different winding operations in dependence, inter alia, of the wire dimension and the demands to storage capacity of the wire magazine and winding accuracy. In practice, this has resulted in a limited applicability of a specific winding machine, so that it has often been necessary to change to a different machine. For example, it has not been possible in the prior art to use the same machine both for wire winding and so-called bandaging, i.e. winding of a wire-wound core with insulation tape.
Moreover, the prior art machines do not fulfil the requirements with respect to safety of labour, since the wire magazine and the guide, and driving means therefor must normally be freely accessible in order to enable reasonably easy operation of the machine.
From U.S. Pat. No. 3,669,365 a winding machine of the single-ring type is known, in which the wire magazine has the form of a shuttle which must be filled with wire in a separate operation preceding the winding operation, since the filling of wire into the magazine requires an opposite direction of rotation of the wire magazine relative to the winding operation. In this prior art machine, the shuttle holder which is firmly connected with the machine frame and is provided with guide means is made openable to receive different shuttle types. The arrangement of guide means in this prior art machine comprises guide rollers both on the external side of the shuttle and on the internal side facing the axis of revolution, and already for this reason this machine is not suitable for use with wire magazines of the above-mentioned kind in which wire is supplied to the magazine in the same operation as the winding operation in that wire is drawn out from the magazine through a bottom slit.